Field mutants

Field mutants Four EDDP-resistant mutants of D. oryzae were obtained from EDDP-treated paddy rice fields showing no disease control. 

Stable and virulent mutants For P. oryzae, one EMS (POLR-1), the adapted mutants (POLR-2 and POLR-3) and one UV mutant (POLR-4) and for D. oryzae, one EMS mutant (DOLR-1) and four field mutants (DOFR-1, DOFR-2, DOFR-3 and DOFR-4) were chosen based on their stability and pathogenicity. 

In the 1950s, a group of coryneform bacteria which accumulate a large amount of L-glutamic acid in the culture medium were isolated (21). The use of mutant derivatives of these bacteria offered a new fermentation process for the production of many other kinds of amino acids (22). The amino acids which are produced by this method are mostiy of the T.-form, and the desired amino acid is singly accumulated. Therefore, it is very easy to isolate it from the culture broth. Rapid development of fermentative production and en2ymatic production have contributed to the lower costs of many protein amino acids and to their availabiUty in many fields as economical raw materials. 

Fig. 13. VTMCD spectra of [Fe3S4] clusters in wild type and mutant forms of P. furiosus Fd. In each case the spectra shown were recorded at temperatures between 1.5 and 50 K with an applied magnetic field of 4.5 or 6 T (all transitions increase in intensity with decreasing temperature).

For future research in this field, in addition to physiological and biochemical approaches, genetic analysis will be essential in the establishment of causal relationships between the induction of a stress protein and the establishment of tolerance to the stress condition. In most cases it is not difficult to detect the induction of new proteins during stress. However, the induction of new proteins does not necessarily establish stress tolerance it may well be the consequence of damage caused by stress conditions. Thus, genetic mutants will be necessary to test the physiological role of a stress protein. 

Ivancich, A., P. Dorlet et al. (2001). Multifrequency high-field EPR study of the tryptophanyl and tyrosyl radical intermediates in wild-type and the W191G mutant of cytochrome c peroxidase. J. Am. Chem. Soc. 123 5050-5058. 

Fields, B.A., F.A. Goldbaum, W. Dall Acqua, E.L. Malchiodi, A. Cauerhff, F.P. Schwarz, X. Ysem, R.J. Poljak, and R.A. Mariuzza. 1996. Hydrogen bonding and solvent structure in an antigen-antibody interface. Crystal structures and thermodynamic characterization of three Fv mutants complexed with lysozyme. Biochemistry 35 15494-15503. 

The MetPAD test kit (Group 206 Technologies, Gainesville, Florida) has been developed for the detection of heavy metal toxicity. It has been used to determine the toxicity of sewage water and sludge, sediments, and soil [41]. The test is based on the inhibition of (3-galactosidase activity in an Escherichia coli mutant strain. Performance of the test does not require expensive equipment and it is therefore easily applied as a field test. 

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